Resend

Email API platform built for developers to send transactional and marketing emails with high deliverability. Offers a simple REST API and SMTP gateway alongside SDKs for Node.js, Ruby, Python, PHP, Go, Rust, Java, Elixir, and .NET. Designed to reach inboxes instead of spam folders through domain authentication, multi-region delivery, and deliverability tooling.

Trusted by companies such as Vercel, Infisical, Warp, and Mintlify. Differentiates from Mailgun, SendGrid, and Mandrill through a developer-first design, minimal API surface, and tight integration with React Email for building templates in React instead of HTML. Runs test mode to simulate events without sending real mail, and ships modular webhooks for delivered, opened, bounced, clicked, and complaint events.

Key capabilities:

• REST API and SMTP with official SDKs for major languages and frameworks including Next.js, Remix, Nuxt, Express, Hono, and Astro
• React Email integration for building templates as React components without table layouts
• Multi-region delivery in North America, South America, Europe, and Asia for lower latency
• Domain authentication with DKIM, SPF, DMARC, and BIMI plus managed dedicated IPs with auto warmup
• Webhooks for real-time delivery, open, click, bounce, and complaint notifications
• Audiences, broadcasts, and contact management with analytics and suppression lists

Developers use it for password resets, order confirmations, welcome sequences, and marketing newsletters. Integrates via npm packages or REST calls, works with React Email for in-editor template development, and connects to n8n, Segment, and other automation tools. Well suited for startups and teams migrating from legacy email providers seeking a simpler API and better deliverability.